A conventional transfer press has a press body in which a plurality of work stations are formed, and a workpiece is continuously fed from an upstream side of the work stations to a downstream side thereof. However, in a large-sized transfer press of such a structure, the transfer press has a long overall length, and it was difficult to convey the transfer press from a press manufacturing factory to a press setting place.
For this reason, in order to solve such a problem, Japanese Patent Laid-open Publication No. HEI 2-247031 provides a transfer press having a large body which is capable of being easily conveyed with the crown sections and bed sections divided at during manufacturing, and then assembled them into a crown and a bed at the press setting place.
However, the transfer press disclosed in this publication has a structure that two tie rods penetrate through an upright disposed between adjacent places at which two continuous manufacturing steps are performed and the crown and the bed are firmly coupled together. According to such a structure, it is necessary to make large a width of the upright in the bilateral direction (work conveying direction), which results in an elongation of a distance between the respective work stations, and hence, the press body is made large, thus being inconvenient. Furthermore, the weight of the upright is also increased as the width thereof is made large, thus also being inconvenient.
Furthermore, in the case of the upright having an increased width, the penetration holes through which the tie rods penetrate must be formed, respectively, in the uprights, requiring considerable work, thus being inconvenient.
In order to solve such inconveniences, Japanese Patent Laid-open Publication No. HEI 8-52597 provides a transfer press such as shown in FIG. 1.
The transfer press shown in FIG. 1 has a structure such that a crown a and a bed b are divided into a plurality of crown sections and bed sections and a plurality of uprights c are disposed between the respective crown and bed sections a and b. The crown section a and the bed section b are firmly fastened by one tie rod d inserted into each upright c. Key grooves e are formed in upper surfaces of the adjacent crown sections a, tie plates g are fitted to keys f engaged with the key grooves e, and the tie plates g are fastened by nuts h screwed onto upper ends of the tie rods d, respectively, thus positioning the respective crown sections a.
According to the transfer press of the structure mentioned above, however, since the divided surfaces i of the crown sections a and the central axis of the tie rod d are coincident with each other, in a case where the upper surfaces of the adjacent crown sections a have differences due to, for example, manufacturing errors at the time of manufacturing the crown a, the bed b and the upright c, a fastening force applied at the tie rod fastening step is not uniformly applied to the adjacent crown sections a, so that the fastening is not reliably performed. Moreover, at such a time, there will cause such a case that an unbalanced load is applied to the tie plate g and the key f, so that these members may be damaged or positioning performance may be made worse, thus also being inconvenient.
Furthermore, since the respective crown sections a are large in size and large in weight, many steps are required for forming the key grooves e in the upper surfaces of the crown sections a with high performance, thus being inconvenient. The use of the tie plates g and the keys f increases numbers of parts or members to be used, resulting in increased manufacturing cost.
The present invention was conceived to improve the inconveniences encountered in the prior art mentioned above and to provide a transfer press having a structure such that a crown and a bed are divided into a plurality of sections, which are then coupled together by means of horizontal coupling means, so as to reduce the number of parts or members to be used and to reduce the manufacturing cost.